How Glow-in-the-dark works• All glow-in-the-dark products contain phosphors• A phosphor is a substance that radiates visible light after

being energized.

Blue, Green and Red Phosphors

Glow in the dark spectra

• Phosphors have three characteristics:• The type of energy they require

to be energized• The color of the visible light that

they produce• The length of time that they glow

after being energized (Persistence)

• Glow-in-the-dark objects are photoluminescent and phosphorescent

• Steps involved in phosphorescence• Electrons are excited• Excited electrons drop to a

lower, but still excited intermediate level (Most light emitted here)

• Electrons drop to ground state

Glowing Pickle• Steps to make a pickle glow.

–Large current flows through the pickle–Pickle quickly heats up near the electrodes due to current–At the electrodes water vaporizes.–The region near one end goes dry first, so the large current

stops and all the voltage drops across this dry region.–In this dry region impact ionization now takes place.

• e collides with Na, ionizing it etc.: e + Na → e + Na+ + e ...

• Na+ relaxes emitting a photon: Na+ + e → Na* → Na +

–Just like in a Na vapor lamp!Lithium Chloride Pickle

• We used a re-pickled pickle.

• The pickle was “reconstituted” by soaking it in lithium chloride.

• This caused there to be some red light in the spectrum along with the yellow light from the sodium.

The Pickle

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Big lithiumpickle

Li Na pickle

pickle pickle

Wavelength (nm)Lithium Pickle peaks at 610nm, 670nm & 813nmSodium pickle peaks at 589nm, 767nm & 770nm

Glowing Pickle Specta